The present invention relates to flywheel systems. More specifically, the invention relates to a flywheel system having a plurality of flywheel power units suspended from a common mounting frame in a manner that permits the flywheel power units to gimbal in relation to a surface upon which the flywheel system is mounted.
A typical flywheel unit comprises a relatively heavy rotatable mass, or flywheel, suspended from a shaft. The shaft is rotatably coupled to a casing via one or more bearings. Flywheel units have been proposed for use in mobile applications, e.g., as energy-storage units that assist in the acceleration and deceleration of a motor vehicle, or as batteries that convert mechanical energy stored in the flywheel into electrical energy using a motorgenerator incorporated into the flywheel unit.
The proposed use of flywheel units in mobile applications raises certain issues not present in stationary applications. In particular, the rotating flywheel generates gyroscopic moments when the flywheel unit undergoes angular displacement about any axis other than its axis of rotation. These gyroscopic moments can induce substantial forces on the bearings within the flywheel unit, and on the mounts that support and restrain the flywheel unit. Gyroscopic moments can thereby increase friction and wear in mechanical bearings, and can increase the power requirements of electromagnetic bearings. The increases in friction or power requirements increase the rate at which the energy stored in the rotating flywheel is drained, thus lowering the useful energy-storage capacity of the flywheel unit.
The effects of gyroscopic moments in a flywheel unit can be alleviated by suspending the flywheel unit in a manner that permits the unit to freely incline in relation to its supporting surface, i.e., by gimbaling the flywheel unit. Gimbaled mounts, however, present certain disadvantages in comparison to rigid mounts. For example, gimbaled mounts typically occupy a greater volume than rigid mounts. In addition, gimbaled mounts usually have a higher parts count than rigid mounts, and include moving components. Hence, a gimbaled mount is typically heavier, more costly, more complex, and less reliable than a rigid mount of comparable capacity (these characteristics are particularly disadvantageous in mobile applications.)
The disadvantages associated with gimbaled mounts may be outweighed by the benefits of such mounts in applications that involve a single flywheel unit. The disadvantages of gimbaled mounts can easily exceed their resultant benefits, however, in applications involving multiple flywheel units. Hence, an ongoing need exists for a flywheel system having multiple flywheel units mounted in an arrangement that alleviates the effects of gyroscopic moments on the flywheel units and their corresponding mounts, while avoiding the above-noted disadvantages usually associated with multiple gimbaled mounts.
A presently-preferred embodiment of a gimbaled flywheel system adapted for use on a supporting surface comprises a pivot adapted to be mounted on the supporting surface. The gimbaled flywheel system also comprises a mounting frame comprising a first frame member coupled to the pivot and extending in a first direction, and a second frame member fixedly coupled to the first frame member and extending in a second direction substantially perpendicular to the first direction. The mounting frame is pivotable about an axis extending substantially in the second direction when the pivot is mounted on the supporting surface.
The gimbaled flywheel system further comprises a plurality of flywheel units. The flywheel units each comprise a casing pivotally coupled to the second frame member and being pivotable about a respective axis extending substantially in the first direction, and a flywheel rotatably coupled to the casing and being rotatable about a respective axis extending substantially in a third direction, the third direction being substantially perpendicular to the first direction.
A presently-preferred embodiment of a gimbaled flywheel system mountable on a supporting surface comprises a first and a second pivot each being adapted to be mounted on the supporting surface. The gimbaled flywheel system also comprises a mounting frame comprising a first frame member coupled to the first pivot, an opposing second frame member coupled to the second pivot, and a third and an opposing fourth frame member each being fixedly coupled to the first and the second frame members. The gimbaled flywheel system further comprises a plurality of flywheel units each comprising a casing pivotally coupled to the third and the fourth frame members, and a flywheel rotatably coupled to the casing.
A presently-preferred embodiment of a gimbaled flywheel system adapted for use on a mounting surface comprises a pivot adapted to be mounted on the mounting surface. The gimbaled flywheel system further comprises a mounting frame comprising a first frame member coupled to the pivot, and a second frame member fixed to the first frame member. The gimbaled flywheel system also comprises a plurality of flywheel units each comprising a casing pivotally coupled to the second frame member and having a pivotal axis, and a flywheel rotatably coupled to the casing and having an axis of rotation substantially perpendicular to the pivotal axis.
A presently-preferred embodiment of a power-storage system comprises a first and a second pivot each adapted to be fixedly coupled to a mounting surface. The power-storage system further comprises a mounting frame comprising a first frame member coupled to the first pivot, an opposing second frame member coupled to the second pivot, and a third and an opposing fourth frame member each being fixedly coupled to the first and the second frame members. The mounting frame is pivotable about an axis extending in a first direction.
The power-storage system further comprises a plurality of flywheel units each comprising a casing pivotally coupled to the third and the fourth frame members and being pivotable about a respective axis extending substantially in a second direction, and a flywheel rotatably coupled to the casing and being rotatable about an axis extending substantially in a third direction.
A presently-preferred method of mounting a plurality of flywheel units on a supporting surface comprises pivotally coupling an casing of each of the plurality of flywheel units to a mounting frame, and pivotally coupling the mounting frame to the supporting surface.